WebRTC is great
Janus is a cool library (link if you never heard of it : github and good intro link)

But boy is it CPU intensive.

here are some links for the case you’re looking at ways to lower the damage

Client CPU benchmark and how to improve it
https://groups.google.com/forum/#!msg/meetecho-janus/ydGcbMt7IX0/LOGVIA6yjkAJ

Performance analysis of the Janus WebRTC gateway
https://www.researchgate.net/publication/300727546_Performance_analysis_of_the_Janus_WebRTC_gateway

WebRTC – CPU reduction, settings to tweak
https://stackoverflow.com/questions/28590423/webrtc-cpu-reduction-settings-to-tweak

WebRTC SFU Load Testing
https://webrtchacks.com/sfu-load-testing/